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Diffstat (limited to 'Documentation/thinkpad-acpi.txt')
| -rw-r--r-- | Documentation/thinkpad-acpi.txt | 92 |
1 files changed, 75 insertions, 17 deletions
diff --git a/Documentation/thinkpad-acpi.txt b/Documentation/thinkpad-acpi.txt index eb2f5986e1e..ca89711f158 100644 --- a/Documentation/thinkpad-acpi.txt +++ b/Documentation/thinkpad-acpi.txt @@ -161,20 +161,22 @@ system. Enabling the hotkey functionality of thinkpad-acpi signals the firmware that such a driver is present, and modifies how the ThinkPad firmware will behave in many situations. +The driver enables the hot key feature automatically when loaded. The +feature can later be disabled and enabled back at runtime. The driver +will also restore the hot key feature to its previous state and mask +when it is unloaded. + When the hotkey feature is enabled and the hot key mask is set (see -below), the various hot keys either generate ACPI events in the -following format: +below), the driver will report HKEY events in the following format: ibm/hotkey HKEY 00000080 0000xxxx -or events over the input layer. The input layer support accepts the -standard IOCTLs to remap the keycodes assigned to each hotkey. +Some of these events refer to hot key presses, but not all. -When the input device is open, the driver will suppress any ACPI hot key -events that get translated into a meaningful input layer event, in order -to avoid sending duplicate events to userspace. Hot keys that are -mapped to KEY_RESERVED in the keymap are not translated, and will always -generate an ACPI ibm/hotkey HKEY event, and no input layer events. +The driver will generate events over the input layer for hot keys and +radio switches, and over the ACPI netlink layer for other events. The +input layer support accepts the standard IOCTLs to remap the keycodes +assigned to each hot key. The hot key bit mask allows some control over which hot keys generate events. If a key is "masked" (bit set to 0 in the mask), the firmware @@ -256,6 +258,20 @@ sysfs notes: disabled" postition, and 1 if the switch is in the "radios enabled" position. + hotkey_report_mode: + Returns the state of the procfs ACPI event report mode + filter for hot keys. If it is set to 1 (the default), + all hot key presses are reported both through the input + layer and also as ACPI events through procfs (but not + through netlink). If it is set to 2, hot key presses + are reported only through the input layer. + + This attribute is read-only in kernels 2.6.23 or later, + and read-write on earlier kernels. + + May return -EPERM (write access locked out by module + parameter) or -EACCES (read-only). + input layer notes: A Hot key is mapped to a single input layer EV_KEY event, possibly @@ -393,21 +409,63 @@ unknown by the driver if the ThinkPad firmware triggered these events on hot key press or release, but the firmware will do it for either one, not both. -If a key is mapped to KEY_RESERVED, it generates no input events at all, -and it may generate a legacy thinkpad-acpi ACPI hotkey event. - +If a key is mapped to KEY_RESERVED, it generates no input events at all. If a key is mapped to KEY_UNKNOWN, it generates an input event that -includes an scan code, and it may also generate a legacy thinkpad-acpi -ACPI hotkey event. - -If a key is mapped to anything else, it will only generate legacy -thinkpad-acpi ACPI hotkey events if nobody has opened the input device. +includes an scan code. If a key is mapped to anything else, it will +generate input device EV_KEY events. Non hot-key ACPI HKEY event map: 0x5001 Lid closed 0x5002 Lid opened 0x7000 Radio Switch may have changed state +The above events are not propagated by the driver, except for legacy +compatibility purposes when hotkey_report_mode is set to 1. + +Compatibility notes: + +ibm-acpi and thinkpad-acpi 0.15 (mainline kernels before 2.6.23) never +supported the input layer, and sent events over the procfs ACPI event +interface. + +To avoid sending duplicate events over the input layer and the ACPI +event interface, thinkpad-acpi 0.16 implements a module parameter +(hotkey_report_mode), and also a sysfs device attribute with the same +name. + +Make no mistake here: userspace is expected to switch to using the input +layer interface of thinkpad-acpi, together with the ACPI netlink event +interface in kernels 2.6.23 and later, or with the ACPI procfs event +interface in kernels 2.6.22 and earlier. + +If no hotkey_report_mode module parameter is specified (or it is set to +zero), the driver defaults to mode 1 (see below), and on kernels 2.6.22 +and earlier, also allows one to change the hotkey_report_mode through +sysfs. In kernels 2.6.23 and later, where the netlink ACPI event +interface is available, hotkey_report_mode cannot be changed through +sysfs (it is read-only). + +If the hotkey_report_mode module parameter is set to 1 or 2, it cannot +be changed later through sysfs (any writes will return -EPERM to signal +that hotkey_report_mode was locked. On 2.6.23 and later, where +hotkey_report_mode cannot be changed at all, writes will return -EACES). + +hotkey_report_mode set to 1 makes the driver export through the procfs +ACPI event interface all hot key presses (which are *also* sent to the +input layer). This is a legacy compatibility behaviour, and it is also +the default mode of operation for the driver. + +hotkey_report_mode set to 2 makes the driver filter out the hot key +presses from the procfs ACPI event interface, so these events will only +be sent through the input layer. Userspace that has been updated to use +the thinkpad-acpi input layer interface should set hotkey_report_mode to +2. + +Hot key press events are never sent to the ACPI netlink event interface. +Really up-to-date userspace under kernel 2.6.23 and later is to use the +netlink interface and the input layer interface, and don't bother at all +with hotkey_report_mode. + Bluetooth --------- |